Hi – concerning stopcocks, in our street front property the water could be shut off from the basement of the next door building. I guess that was because they were all conjoined and over time no one had the incentive / money to sort it out. There was also an intermediate stopcock at ground floor near the street front entrance door to our building – boxed in at hip level, easily opened. And then one for my flat behind the bath panel. So the message is to speak to neighbours and enquire widely – and communicate in advance so any interruption of supply is flagged clearly. You don’t want bad relations with neighbours!